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Ring-billed Gull
(delawarensis)


IMAGES:

First Cycle
Second Cycle
Adult


DESCRIPTION:

RING-BILLED GULL (18-21"; 47-50") delawarensis

BILL SHAPE: rather slim; larger than Mew; about 3-4x eye diam; gon angle small; long slope of culmen to tip
HEAD SHAPE: rounded but w/ elongated crown; more dove-like than Calif; brow smaller than Calif, heavier than Mew
WING EXTENSTION: long; 1.5x bill length
POSTURE/HABITS:
FIRST CYCLE SECOND CYCLE ADULT
BILL COLOR: flesh to dull yellow w/ usually sharply defined black outer 1/3, extending in on cutting edge; tip may be pale yellow, usually w/ thick black band yellow w/ black subterm band; rarely the band is faint gray
LEG COLOR: pink gray to dull yellow w/ greenish tone yellow to greenish-yellow
IRIS/ORB RING: dark usually as adult pale yellow, rarely dark; orb ring orange-red
HEAD: well defined streaks on crown and aurs, concentrated most around eye; nape more spotted; lores and throat white fine streaking over crown and aurs, densest before eye; heavier spotting on nape fine short streaks over crown and aurs; aur edge paler; thicker spotting on nape and neck sides
UNDERPARTS: white w/ variable spotting across breast and down flanks variable spotting or blotching across upper breast; otherwise white white
PRIMARIES
(folded):
black black A-spots small and decreasing; A7 size of eye; A10 barely visible
PRIMARIES
(in flight):
outer Ps black; inner Ps pale w/ dark subterm spots, creating obvious pale window P7-10 mostly black; tiny mirror on P10 possible; black to P5 or P4 extensive black on P8-10; med mirror on P10; small mirror on P9; black usually on P5, often to P4; gray undersides show no contrast
SECONDARIES
(in flight):
dark w/ pale fringe; underwing coverts white w/ thin dark feather edges as adult, but may have dark marks adult gray w/ thin white trailing edge
TERTIALS: dark g-b w/ pale edges; may include large pale spots at tip of each side of shaft adult gray w/ thin faded white crescent adult gray w/ small faded white crescent, about 1/3 bill length
GREATER COVERTS: whitish w/ two rows of g-b spots or bands, fading quickly to nearly white adult gray w/ hints of pale brown adult gray
LESSER & MED COVERTS: whitish w/ dark interior diamonds, fading quickly adult gray w/ hints of pale brown adult gray
SCAPULARS: adult gray; may have a few dark marks or pale fringes adult gray adult gray w/ no white crescent
BACK: adult gray w/ variably scattered dark marks or pale fringes adult gray adult gray is pale cool gray, like Herring smithson.
RUMP: white w/ scattered dark V-marks white white
TAIL: white w/ broad black subterm band, mottled on outer retrices; variable thinner "shadow bands" at fringe and inside main band; single black band or mostly dark tail rare white w/ variable, usually broken, black subterm band or marks white

The was table created by Steve Hampton and is intended to futher our knowledge of gull identification. Please email me at shampton@ospr.dfg.ca.gov if you have any suggestions for updating or improving this table. Thanks.